USDA changes Tulsa's plant hardiness zone

TULSA, Okla. — Gardeners are likely aware of their plant hardiness zone when it comes to choosing what perennials will survive outdoors through the winter. Those zones have recently been updated by the United States Department of Agriculture (USDA) based upon the 30-year average of the coldest temperature each winter in a given location.

The newest delineation of zones used the 1991 to 2020 coldest average winter temperatures across the United States.

Tulsa among many other locations have fallen into a new zone due to rising winter temperatures overall. The metro area shifted from Zone 7a to Zone 7b.

Tulsa’s average coldest winter temperature jumped about 5.5° causing that shift. While the zones do not showcase what plants due best in a specific climate, they are a good tool to knowing which plants can survive most winters.

Green Country now is made up of Zone 7a north of Tulsa into southeast Kansas, Zone 7b from the Tulsa area to south of I-40. Spots of Zone 8a are now found in southeast Oklahoma as well.

For more on plant hardiness zones and a detailed look at the new map, you can visit the USDA’s Plant Hardiness page .